PROPERTIES AND HYPOGLYCEMIC EFFECT OFTHE INSULINLOADED NANOPARTICLES FOR ORAL ADMINISTRATION

Objective: To investigate the physicochemical properties and hypoglycemic effect of insulinloaded nanoparticles (INSNP) upon rats after oral administration. Methods: The mean diameter, associating ratio and invitro release kinetics of INSNP were investigated. The hypoglycemic effect of the two formulations of INSNP (Ⅰ,Ⅱ) was evaluated on the normal and diabetic rats by measuring the blood glucose levels. Results: The release profiles of INSNP were be well modelled using a biexponential function. The hypoglycemic effect was not significant after oral administration of 10 u/kg INSNP to the normal rats. The average blood glucose levels within 1～12 h dropped 35.0% and 35.5%, respectively, after 5 u/kg of INSNP (Ⅰ,Ⅱ) 　was orally administered to the diabetic rats, while it decresed 60.8% when 10 u/kg of INSNP (Ⅰ) was administered. In comparison with subcutaneous injection of the insulin solution, the pharmacological bioavailability calculated by the timeblood glucose decreased (%) profiles was 27.9% and 28.6%, respectively, for the INSNP Ⅰ and INSNP Ⅱ after oral administration. Conclusion: The hypoglycemic effect of insulin upon diabetic rats could be improved through the proper formulation of nanoparticles.